Twice today, in amongst heavy cycle traffic, I had near misses with other cyclists caused by the other guy not respecting my road position. Sounds high and mighty, I know, but let me explain. First incident, I'm cycling along behind a small van, leaving enough of a gap between me and him so that I don't hit him. I'm in the middle of the lane, its a one way road. other cyclist undertakes me on my left, tries to cut into the gap in front of me, I have to brake hard to miss him because I'm prevented from swerving right because of another cyclist coming up close on that side too. Further on, I'm out in primary, I look over my shoulder, indicate to turn left, brake gently, indicate again, and slap another cyclist in the face as I do so; he's completely missed me indicating and rather than overtaking around the outside he's trying to get through kerb-side. Neither of us came off but he didn't half swear at me. Now, I know, you have to give and take and use primary and secondary road positions as appropriate, but the problem I often have in Cambridge at this time of year is just how many cyclists here are complete muppets who don't know to respect other peoples spacing and road positioning, who don't get why every gap on the road is a good place to dive in to. Whats the best way for dealing with such traffic situations? I'm leaving enough space on the road to be safe when dealing with motorised vehicles, and those gaps get filled with other bikes. Whats the solution?